1992 年 63 巻 5 号 p. 337-340
An experiment with ellipses was conducted to evaluate the validity of Metzger's theory on geometrical illusions (the law of good Gestalt) by examining whether its major axis is underestimated and its minor axis overestimated. If the horizontal or vertical dimension of a circle with a fixed diameter is reduced, “smaller” ellipses with major axes equal to the circle's diameter will be constructed. On the other hand, if the dimension is enlarged, “larger” ellipses with minor axes equal to the circle's diameter will be produced. Ten university students estimated the apparent lengths of such axes. It was found that the major axes were underestimated, while the minor axes were overestimated, irrespective of the relative sizes of the ellipses. The same result was obtained when the orientation of the axis was rotated 90°. These results may be interpreted in line with Metzger's theory to the illusion of major and minor axes in ellipse.